The pandemic has not been the only crisis we’ve been wading through over the past 12 months: 2020 was a banner year in much of Britain for sewage spills. Last July a Guardian investigation revealed that raw sewage had been pumped into English rivers via storm overflows more than 200,000 times in 2019. In November, Surfers Against Sewage (SAS) published data showing that untreated wastewater was discharged on to English and Welsh beaches on 2,900 occasions in a year.
Then last month, under mounting pressure, the Environment Agency published, for the first time, full data on raw sewage discharges last year, showing a 37% year-on-year increase: 3.1m hours of human effluent flows, pumped via storm drains into English waters in some 400,000 occasions.
Not since SAS was founded in 1990 – when untreated wastewater piped directly into the sea and flowing back on to British shores caused a scandal – has so much untreated faeces spread so far. Hugo Tagholm, SAS’s chief executive, says the country is facing “a second wave of sewage pollution”.
All overflows reach the same place. “All of our waterways are connected,” says Tagholm. “It’s one cycle: what goes into our rivers ends up in our ocean.”
The country is belatedly waking up to the crisis. New ideas are being proposed – sustainable drainage, use of artificial intelligence (AI), even doing away with sewers altogether. Meanwhile, communities and increasing numbers of wild swimmers, surfers and paddle boarders are piling on pressure, because the solutions do not only involve water companies and sewers but the fabric of our cities, towns and villages, as well as farms taking responsibility for their polluting runoff.
“Despite the progress that investment has made,” says Tagholm, “we still see thousands of sewage pollution events each year emanating from the combined sewer overflow network on our coastline, and particularly in our rivers.”
In short, Britain literally oozes sewage. How did it come to this? Most Britons don’t think about what happens when they flush their toilets. It probably involves a “combined sewer network”, fed by rainwater – including road and land runoff – and buildings’ waste drains. After the 1990 sewage crisis, the urban wastewater directive stipulated that water companies must treat sewage rather than dump it in the sea. So, on a good day, wastewater flows to the sewage treatment works, where it undergoes filtering, dewatering, processing and recycling.
But good days are increasingly rare. Previously, only freak storms would fill the system to the point that the toxic soup would spill out into waterways (to avoid the even grislier prospect of it spouting back up our drains). Now, however, both the number of houses and the frequency of storms have increased. The system is so far over-capacity that in some areas drizzle can make it overflow – and blockages and fatbergs can cause overflows even when it’s not raining.
“We’ve got 15,000 storm overflows,” says Keith Davis, the Environment Agency’s water-quality regulatory development manager, “and the majority are on the combined sewer network, with about 100,000km of combined sewer in England alone.”
That’s a lot of sewer to manage at the best of times, which these are not, he says. “We’ve got climate change, population growth and urban creep,” meaning the loss of permeable surfaces to absorb rain. “A small-scale example is someone paving over their front garden to provide parking. If a number of people do it, it will increase the runoff.”
In London, sewage overflowing into the Thames has been an urgent problem for many years, with about 39m tonnes spewing into the river each year. The GBP4.2bn Tideway super sewer, under construction since 2016, aims to tackle this. It has been built to last 150 years, but what happens after that? Even bigger and deeper concrete structures? And what about the rest of the country?
James Harrison, head of wastewater assets for Yorkshire Water, thinks hard engineering alone is not a feasible solution. “You can’t typically invest your way out of it by enlarging sewers, pouring lots of concrete and having big tanks. That costs an awful lot of money, and it contains a lot of embedded carbon.”